Metamodeling approach for efficient estimation of optical properties of turbid media from spatially resolved diffuse reflectance measurements

Watté, Rodrigo; Trong, Nghia Nguyen Do; Aernouts, Ben; Erkinbaev, Chyngyz; Baerdemaeker, Josse De; Nicolaı̈, Bart; Saeys, Wouter

doi:10.1364/oe.21.032630

Cited by 27 publications

(12 citation statements)

References 35 publications

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“…The collected light is then sent to a spectrograph and the spatially resolved diffuse reflectance is acquired as function of wavelength (Figure ). A metamodel trained on measurements acquired for a set of liquid phantoms covering a wide range of known optical properties was used to extract the μ a and μ s ′ values from the collected reflectance profiles, described in detail in our previous publication .…”

Section: Methodsmentioning

confidence: 99%

Light distribution and thermal effects in the rat brain under optogenetic stimulation

et al. 2015

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Optical brain stimulation gained a lot of attention in neuroscience due to its superior cell-type specificity. In the design of illumination strategies, predicting the light propagation in a specific tissue is essential and requires knowledge of the optical properties of that tissue. We present the estimated absorption and reduced scattering in rodent brain tissue using non-destructive contact spatially resolved spectroscopy (cSRS). The obtained absorption and scattering in the cortex, hippocampus and striatum are similar, but lower than in the thalamus, leading to a less deep but broader light penetration profile in the thalamus. Next, the light distribution was investigated for different stimulation protocols relevant for fiber-optic based optogenetic experiments, using Monte Carlo simulation. A protocol specific analysis is proposed to evaluate the potential of thermally induced side effects.

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Section: Methodsmentioning

confidence: 99%

Light distribution and thermal effects in the rat brain under optogenetic stimulation

et al. 2015

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“…Thus, an inverse model of light propagation relates the collected signal to optical properties of tissue to extract absorption and reduced scattering coefficients. [10][11][12][13][14] Using a wavelength-dependent linear-square fit of absorption coefficient values and the Beer-Lambert law, the concentrations of individual chromophores (hemoglobin, lipids, water, and others) can be calculated, 15,16 while structural variation of tissue can be derived from the scattering coefficients (amplitude and power) by Mie theory. 17 The current array of studies demonstrates the use of three different optical systems as diagnostic assays to investigate the pathophysiological processes involved in focal traumatic brain injury (TBI).…”

Section: Introductionmentioning

confidence: 99%

Noninvasive assessment of hemodynamic and brain metabolism parameters following closed head injury in a mouse model by comparative diffuse optical reflectance approaches

et al. 2016

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Abstract. Optical techniques have gained substantial interest over the past four decades for biomedical imaging due to their unique advantages, which may suggest their use as alternatives to conventional methodologies. Several optical techniques have been successfully adapted to clinical practice and biomedical research to monitor tissue structure and function in both humans and animal models. This paper reviews the analysis of the optical properties of brain tissue in the wavelength range between 500 and 1000 nm by three different diffuse optical reflectance methods: spatially modulated illumination, orthogonal diffuse light spectroscopy, and dualwavelength laser speckle imaging, to monitor changes in brain tissue morphology, chromophore content, and metabolism following head injury. After induction of closed head injury upon anesthetized mice by weight-drop method, significant changes in hemoglobin oxygen saturation, blood flow, and metabolism were readily detectible by all three optical setups, up to 1 h post-trauma. Furthermore, the experimental results clearly demonstrate the feasibility and reliability of the three methodologies, and the differences between the system performances and capabilities are also discussed. The long-term goal of this line of study is to combine these optical systems to study brain pathophysiology in high spatiotemporal resolution using additional models of brain trauma. Such combined use of complementary algorithms should fill the gaps in each system's capabilities, toward the development of a noninvasive, quantitative tool to expand our knowledge of the principles underlying brain function following trauma, and to monitor the efficacy of therapeutic interventions in the clinic.

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“…Accurate separation of the absorption and scattering properties would require at least 2 uncorrelated optical signals measured on the same sample . The sensor configuration which measures the diffuse signal resulting in the most accurate separation of the BOP can be found through light propagation calculations.…”

Section: Results and Discussionmentioning

confidence: 99%

Near-infrared bulk optical properties of goat wound tissue and human serum: consequences for an implantable optical glucose sensor

et al. 2015

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Near-infrared (NIR) spectroscopy offers a promising technological platform for continuous glucose monitoring in the human body. Moreover, these measurements could be performed in vivo with an implantable single-chip based optical sensor. However, a thin tissue layer may grow in the optical path of the sensor. As most biological tissues are highly scattering, they only allow a small fraction of the collimated light to pass, significantly reducing the light throughput. To quantify the effect of a thin tissue layer in the optical path, the bulk optical properties of serum and tissue samples grown on implanted dummy sensors were characterized using double integrating sphere and unscattered transmittance measurements. The estimated bulk optical properties were then used to calculate the light attenuation through a thin tissue layer. The combination band of glucose was found to be the better option, relative to the first overtone band, as the absorptivity of glucose molecules is higher, while the reduction in unscattered transmittance due to tissue growth is less. Additionally, as the wound tissue was found to be highly scattering, the unscattered transmittance of the tissue layer is expected to be very low. Therefore, a sensor configuration which measures the diffuse transmittance and/or reflectance instead was recommended. (a) Dummy sensor; (b) explanted dummy sensor in tissue lump; (c) removal of dummy sensor from tissue lump; and (d) 900 µm slices of tissue lump.

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Metamodeling approach for efficient estimation of optical properties of turbid media from spatially resolved diffuse reflectance measurements

Cited by 27 publications

References 35 publications

Light distribution and thermal effects in the rat brain under optogenetic stimulation

Light distribution and thermal effects in the rat brain under optogenetic stimulation

Noninvasive assessment of hemodynamic and brain metabolism parameters following closed head injury in a mouse model by comparative diffuse optical reflectance approaches

Near-infrared bulk optical properties of goat wound tissue and human serum: consequences for an implantable optical glucose sensor

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